The Amazing Potato Diet Can a guy live on spuds and milk alone?

I heard it’s possible to live for an extended period of time, not just short-term, on nothing but potatoes and milk. Is there any truth to this? If I could really get all the nutrients I need from just potatoes and milk, it sure would make my grocery shopping easier. —Joshua B., Olney, Md.

Excellent question, Josh. With hard times coming, we’re all going to have to economize. The good news: A spuds and milk diet definitely has possibilities—the Irish, to cite the best-known example, got by mainly on potatoes until the infamous blight of 1845 wiped out their main course. The bad news: (1) Considering the quantities you’re going to have to eat, you’d better really like potatoes. (2) If you’re literally going to eat nothing but potatoes and milk, you risk—brace yourself—serious molybdenum deficiency.

Years ago I tackled the question of whether you could live by bread alone. Answer: Yeah, for about six months, but then you’d die of scurvy. Things won’t be anywhere near that bad on milk and potatoes. Before the Great Famine, the traditional Irish peasant meal consisted mainly of potatoes, milk, oats, beans, barley, and bread. Potatoes were the mainstay. As the years grew leaner, dairy products largely disappeared from the Irish diet, since poverty forced many farmers to sell their milk to pay rent. By the time the famine hit, the peasants were eating pretty much just potatoes, supplemented with some salt fish and oatmeal. I’ve seen it said that a third of the population lived on potatoes and nothing else, although that seems doubtful, as we’ll see. Edward Wakefield, an English land agent and amateur social scientist who traveled Ireland from 1809 to 1811, calculated each Irish peasant family member consumed 5.5 pounds of potatoes per day. An 1846 source claims a working man needed at least 8 pounds of potatoes a day to survive if nothing else was available; a typical family of six would need 26 pounds.

How did the Irish do on this diet? We can’t be certain—nobody was conducting nutrition studies in those days. But there’s reason to believe they were healthier than you might guess. In the century before the famine, Ireland had the highest birthrate in western Europe. Some credit potatoes, saying the availability of easy-to-grow, easy-to-cook spuds made it practical to raise large families. Telling evidence on this score, one historian writes, “is that the Irish in general and Irish women in particular were widely described as healthy and good-looking.” I don’t know about you, Josh, but any diet that gets results like that is good enough for me.

OK, history lesson’s over. Could someone subsist solely on potatoes and milk? I had my assistant Una run a spreadsheet on key nutrients. Looking only at vitamins and minerals for which a recommended daily allowance has been established, we find a diet of vitamin-D-fortified whole milk and potatoes stacks up pretty well, providing at least some of all known dietary needs except molybdenum. For example, if you’re an active male between 19 and 30, of average height and weight, then one gallon of milk and eight pounds of potatoes will supply the RDA of most nutrients, falling a little short on the iron, folate, and niacin fronts, missing a lot of vitamin E, and striking out completely on molybdenum. Chug two gallons of milk with your spuds and all you’re missing is about two-thirds of your vitamin E and, of course, your molybdenum. Not so nuts about milk? Fine, cut it down to a quart and choke down 14 pounds of potatoes instead. Now you’re short on zinc, folate, niacin, vitamin E, and way low on vitamin A. And alas, still no molybdenum.

So what happens if you starve yourself of molybdenum? According to one nutritional reference book, “signs of molybdenum deficiency...are headache, rapid breathing and heart rate, nausea and vomiting, acute asthma attacks, visual problems, disorientation, and, finally, coma.” However, you don’t need much of the stuff—the RDA is only 45 micrograms—and good sources include lentils, split peas, green beans, cauliflower, and, significantly, oatmeal. Since we have no indication that a third of the Irish population was in a coma prior to 1845, my guess is that reports of potato-only diets in the pre-famine era were exaggerated and that inhabitants of the Emerald Isle were getting sufficient oatmeal and other foods to meet their micronutrient needs.

What lessons does all this hold for you, Josh? (1) While no sane nutritionist would recommend a diet consisting of just two foods, if in the interest of economy you need to heavy up on a couple, you could do a lot worse than potatoes and milk. Potato historians sing the praises of this miracle tuber for elevating humankind from the constant threat of starvation. (2) Notwithstanding the potato’s virtues, make sure you eat your oatmeal too. —Cecil Adams

Is there something you need to get straight? Take it up with Cecil on the Straight Dope message board,

Our Readers Say

Potatoes are a toxin for anyone with type A blood. Better to eat brown rice and olive oil if you could only live on two things. Michio Kushi, a macrobiotics student Japan's George Osawa who actually tried it if I am not mistaken, said if you had to live on one thing brown rice would be it. I added the olive oil so the roof of your mouth doesn't dry out.
The blood type diet is BS.
I think blue-green algae (spirulina) has a wider array of vitamins and minerals compared to potatoes and brown rice. I wouldn't want to live off algae though, but if it was only 1 food, I'd have to pick algae to make sure I was healthy enough.
It is quite possible to live on a potato diet or close to it. Note this comment by Dr. Hindhede of Denmark:

Dr. HINDHEDE said that his endeavour had been for many years to try to ascertain what food would give the best results so far as health was concerned. When he lived on meat it made him ill. On the other hand, when he lived on potatoes he felt well. Frederic Madsen, a patient, who afterwards became his assistant, lived on a diet consisting only of potatoes and margarine, and worked long hours of hard manual labour, and was quite well. He did not feel so well on a raw fruit diet as he did on a potato diet. Twenty years ago he (Dr. Hindhede) announced that he himself could live on 3d. a day, and the statement made a great sensation in Denmark. After alluding to the experiences of Denmark during the rationing period brought about by the War, the speaker said that the farm labourers, who were supposed to live on a starvation diet, had the lowest death-rate of all, while the death-rates for doctors and butchers were among the highest of all! It was a true economy to live long and healthily, but it was a sheer extravagance to eat and drink and smoke oneself to death. ...

Here is another report by the same doctor. During a period of shortages during the first world war, Denmark had practically no coffee, tea, sugar, oranges, lemons, or liquor and very little meat.

The people lived on black bread, potatoes, and vegetables mostly. The death rate dropped to the lowest level ever recorded in a European country, a third less than the prewar death rate and 17% lower than the previous record.
To put it in sensible terms, don't be afraid of health issues if you want to live on potatoes as long as you include some whole grains, fruit, green vegetables, and possibly a little meat, poultry and fish.
Get on the bran-waggon. Take a trip to bean town!
Would a diet of potatoes, split peas, greens, oats or barley with a weekly serving of sardines be ideal in terms of providing nutrition as well as economical? I've excluded milk from this proposed diet. Would this suffice?
i have had gastric banding and lost 61kg by eating healthily and in small quantities for one year. i fell pregnant so had to have the fill removed for the babies nutrition. after the baby was born i had the fill put back into the band at which time bought on severe reflux.

anyway milk and potatoes help relieve the reflux and are the only two foods that i have found that i can eat without pain.

I have now been living solely on potatoes and milk (with milo added coz i hate milk generally) for about 1 month now and although i feel very healthy i have not lost any weight but nor have i put any on.

i do find this combination is very satisfying to the hunger and i am not sick of this diet yet but i suppose you really have to like potatoes and/or milk to do this.

i dont plan on doing this long term, just until i can get into see the surgeon

I believe the pasturization of milk is the reason molybdenum is not present in a "milk and potato" diet. I've heard Molybdenum is present in raw, unpasteurised milk. It can be obtained pretty safely too, if you happen to have a dairy that tests the milk for any dangerous bacteria before giving it to you for consumption. I am pretty sure the only way to obtain raw milk is by getting a cow share directly from a dairy. It is surprisingly healthy stuff! I am fortunate to live near a dairy that tests each batch for the stuff pasteurisation is supposed to kill, so their share holders know it is safe)...and let me tell you something that shocked me. I once forgot a jar of milk in the back of the fridge for a few weeks and was stunned that I could see no visible mold. Out of curiosity, I let it sit three months, and it NEVER grew any mold AND did not have an unpleasant odor when I opened the lid to clean out the jar!! I thought for sure I'd have to just throw the thing away, but it wasn't gross at all. Anyway, after reading up on milk, it turns out people really can (and have) live exclusively on it and if supplemented with potatoes, it might possibly be a healthy diet.

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